Light biostimulation has been recognized as a method for providing stimulation to the scalp which has beneficial and therapeutic effects in terms of stimulating the natural growth of hair. For example, low level laser light is believed to enhance the physiological state of the scalp and encourage hair growth when radiated onto the hair follicles on the scalp. Non-coherent light sources such as light emitting diodes (LED) have also been described in this context.
A number of hand held devices have been designed to exploit the biostimulation effects of light sources such as low level laser and LED in a convenient and portable format.
WO01/60457 describes a hand-held, comb-like device emitting laser beams from laser diodes set in a row centred between two parallel rows of teeth for parting hair. The parting of the hair by the comb teeth is said to improve contact between the laser beam or beams and the scalp to be treated.
WO02/102228 describes a similar device, further including a stepped beam splitting reflector which splits one or more laser beams to allow a laser to simultaneously provide multiple laser beams which are distributed across a segment of an individual's scalp. The beam splitting reflector is mechanically aligned with the laser source and has a zigzag structure that mechanically deflects portions of the laser beam as it passes over the peaks of the beam splitting reflector. The portions of the laser beam form a line of reflected laser beams that project towards the users scalp.
In use, the devices described in WO01/60457 and WO02/102228 emit a narrow strip of parallel light beams from the comb housing onto the scalp. This produces a narrow strip of small, discrete beam spots on the surface under treatment. A problem associated with this pattern of scalp irradiation is that a proportion of the hair follicles present in the surface under treatment may be inadequately irradiated, or not irradiated at all, due to the size and spacing of the beam spots when applied to the scalp. This proportion may be especially significant in areas where the density of hair follicles is high. Repeated passage of the device over the area in question is not a satisfactory solution since there is an overall limit to the amount of laser power that can be applied to a person's scalp before the benefits of laser treatment are outweighed by more harmful conditions such as scalp redness, dryness and peeling.
The object of the present invention is to improve the pattern of scalp irradiation delivered from a hand held scalp treatment device using light for the stimulation of hair growth.
The invention solves the problem of uneven or inadequate scalp irradiation by means of a configuration which channels light through a plurality of hollow tines and spreads the light outwardly from the ends of the tines onto the surface of the scalp to be treated.
U.S. Pat. No. 5,303,722 describes a light comb including a plurality of comb teeth, a device for guiding light from a light source through the comb back into the comb teeth, and a device for radiating the light from the comb teeth. However, the purpose of the device of U.S. Pat. No. 5,303,722 is to selectively irradiate hair to be bleached which is located between the teeth of the comb, and not the scalp. Concave mirrors are used in the tips of the comb teeth to guide light away from the scalp and into the intermediate spaces between the comb teeth.